Man-hole for underground electric conduits



No Model.)

W. H. HART. MAN HOLE EOE UNDERGROUND ELECTRIC 'GONDUITS.

No. 443,992. Patented Ja11.6,1891.

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A UNITED STATES PATENT OEEICE.

IYIIILIAM H. HART, OF BROOKLYN, NEIY YORK.

MAN-HOLE FOR UNDERGROUND ELECTRIC CONDUITS.

SPECIFICATION forming part of Letters Patent No. 443,992, dated January 6, 1891.

Application filed March 22, 1890.

To all whom it may concern:

Be it'known that I, TILLIAM H. HART, of Brooklyn, in the county of Kings, State of New York, have invented certain new aud useful Improvements in Man-Holes for Underground Oonduits, of which the followingT is a specification.

As is well known, in all subway systems in cities where the ground is more or less impregnated with illuminating or fuel gas, gas escaping from mains laid in the streets finds its Way by infiltration into the man-holes and explosions, expensive, troublesome, and dangerous to life occur. NVhile more or less gas may force itself into the ducts or pipes of the conduit system, the principal ditliculty has been due to the infiltration of the gas through the walls of the man-holes.

The object of my invention is to so construct the man-holes and connect the ducts with them as to prevent the entrance of gas. This I accomplish by a new and improved construction of man-hole.

A further object of my invention is to prevent the shocks and jars due to passing vehicles from injuring the walls of the man-hole and impairing the integrity of the joint between the tops of the walls and the top or cover section of the man-hole.

In the accompanying drawings, Figure l is a plan view showing a man-hole with the cover partly broken away and one-half of the man-hole in horizontal section, taken on the line where the pipes or ducts enter its walls. Fig.2 is a vertical longitudinalsection through the same.

In building my improved man-hole I proceed as follows: A suitable excavation hav ing been made, I place in the bottom a layer of cement of suitable character-such, for instance, as Portland or Rosendale cementmixed with sand, gravel, or broken stone. Upon this base, which is indicated in the drawings by the letter A, I then spread a layer of pitch or asphaltum, or some such suitable material or mixtures thereof that are impervious to air, gas, and water. This layer B of material is placed down while in a fluid, semi-fluid, or plastic state, so that it will become compact and homogeneous. Ithen build Serial No. 344,911. (No model.)

direct-ly upon the layer of material B double walls O D, preferably of brick laid in some suitable cement, and from time to time Ifll or pour in between the inner and outer walls, and while in a more or less liquid state, material such as the layer B is composed of, and this material forms between the inner and outer walls a compact homogeneous filling B', impervious alike to air, gas, and moisture. At such points as may be desired I place cross-tie plates a to connect and brace the inner and outer walls, as shown.

At the top of the walls, and preferably directly upon the central filling B', I lay a yielding or elastic gasket E. The gasket may be of rubber or other like suitable elastic or yielding material; or it may be of felt or some absorbent material soaked with pitch or asphaltum or other suitable composition. I may on each side of this gasket, as shown, place a layer F of the composition forming the filling B; but I prefer to place the layer F on the outside only. On top of the gasket and layers of material F the ordinary manhole cap or cover-section G is placed, andthis cap is of course provided with the usual cover or covers G. The cap, resting upon the more or less yielding base formed by the gasket, is capable to a certain extent of yielding to the shocks and jars from the vehicles passing over the roadway, and the integrity of the joint between the top of the conduit-walls and the cap is therefore much less liable to be impaired than where the base or support of the cap is a perfectly rigid one. The cap, being placed in position while the layers of com po sition F are in a more or less plastic condition, may readily be properly seated upon the gasket and layers of composition to form a perfectly tight joint, since both the composition and the gasket will yield to the pressure of the cap. This construction should not be confounded with the mere packing of amanhole cover.

Where the ducts or pipes pass through the walls of the conduit,I may employ the following construct-ion: An opening H is left in the wall and the pipes I are passed through it. I then, using suitable guards or shields to confine the material, pour in the filling B2 of IOO 2 Maese the composition which l ani using. This forms a 'tight j'o'inft around the ends of all the pipes and Aperfectly'unitesivith the filling:l B.

I by preference place upon the layer B forming` the Iioor of the conduit a layer of cement A', such as kthe base-layer A is composed of. This is done to protect the composition layer B.

With a man-hole thus constructed it is impossible for gas to force its way in from the surrounding earth, and liability of explosion is reduced to a minimum.

I claim as my invention- 1. In a man-hole of an underground conduit system, the combination, With a base or iioor of material impervious to gras and moisture, of the double Walls C D, built upon said base and having the interposed Iilling,` B of composition impervious to gas and Wat-er beneath both Walls.

2. In a man-hole ol an underground conduit system, the combination, substantially as set forth, of the base A, the layer of composition B, the double Walls C D, both resting` on the layer B, and the composition filling B.

3. In the man-hole of an underground conduit system, the combination, substantially as set forth, Aof. the double walls 01D, having an opening thrgi'gh wvh'ichth'e pipes-fer ducts enter, a illi'ng=B of composition between the 3o double Walls, and the body of composition B2, poured around 'the ends of the ducts and unitin g with the filling B', as described.

4. 'In a man-hole of an underground couduit system, the combination of the conduit- 3 5 Walls of masonry, the cap or cover, the cover section or casting on- Which the cover rests, and a yielding gasket interposed between the cover-section and the walls of the man-hole to prevent jarring and loosening,` of the walls, 4o

substantially as described.

5. The combination, substantially as set forth, of the man-hole Walls, a gasket of yielding material laid around its upper edge, a

layer of compositiomsuch as pitch or 'asphal- 45 

